Man, that would probably require a program that can scan your drive and find files that have the same CRC, which may take a minute, but that would be the only thing that I could think of that would differentiate between audio, video, pics, etc...

That's part of the reason I have had such a sticky collection policy...I usually tag things and move them right away, but I too stumble across dupes from time to time...It will be like I'll have something named AYHJA Movie.mpg and have Another one named AYHJA - Movie (Sc 1).mpg...Or, I'll have .mpg or .mpeg files of the same name, or .mpg versions of a video and then a .wmv version...Or I'll have a bootleg version laying on my HDD after the DVDRIP has come out...A CRC scanner won't work for those files...

So, that little method of CRC check may work for images, but for those heavy hitters size wise, you may have to do some lifting...

I suppose you could hedge some time by first knocking down those kinds of discrepancies...With music, you use your dominant format, say .mp3, and then do an extension search on your lesser formats, like .wma...And then do some cross checking there...

The new Firefox (57) is significantly different- a whole bunch of extensions aren't working right now (and might not be compatible for weeks if not months) and while I've found one alternative for downloads it's kind of a mixed bag.